1. Field of the Invention
The present invention relates to a refractory for use in casting operations which has superior spalling resistance and corrosion resistance when used as a lining in vessels for molten iron and steel production.
2. Background Art
Materials such as the alumina-spinel material disclosed in Japanese Patent Application, First Publication, Laid-Open No. Sho 64-87577, the alumina-magnesia material disclosed in Japanese Patent Application, First Publication, Laid-Open No. Hei 5-97526, and the alumina-spinel-magnesia material disclosed in Japanese Patent Application, First Publication, Laid-Open No. Hei 3-23275, have been proposed as refractories for use in casting operations (hereinbelow referred to as "casting materials") which are used in the lining of molten steel ladles, vacuum de-gassing vessel, tundish, and the like.
These materials possess superior longevity as a result of the synergistic effects of the volume stability of the alumina and the resistance to corrosion of the magnesia or the spinel.
Recently, the conditions of use of vessels for molten steel have become extremely severe as a result of increase in molten steel temperature, extending of holding time, gas-blowing agitation, and the like. As a result, the conventional materials described above do not possess sufficient durablity and higher quality materials have been strongly sought.